My concern with “Phase 2” is that it was initially “Bring Gutenberg into the Customizer,” and was eventually reduced down to “starting with only widgets.” This shows that Phase 1 was still incomplete, and released prematurely as the majority of work that has been focused on in Phase 2 is not really overly relevant to this goal.

This is a great step in converting widgets to blocks, and outlining a definite way for things to be done and why the solution determined is the way to go moving forward, but this to me doesn’t lend itself to “Phase 2” and seems like it should’ve been part of the overall roadmap in the first place. A lot of developers are very uncertain as to what Phase 2 will bring, and it’s not clearly being stated as to how it will impact plugins, and themes. I get the whole “well we don’t know yet” part of things, but at some point it needs to be known – otherwise work being done doesn’t have a real direction or purpose to a goal. It’s almost impossible for a theme developer to plan anything around Gutenberg, which was recognized from the first Phase, and many theme developers when questioned about integration have explicitly stated they chose to “ignore it”.

In relation to the customizer, in December we had screenshots showing a proposition, and to date the next “biggest” update towards this goal has been a screencast of the same proposed idea, but not any code referenced in any of the discussions or repos that show what is being done.
Reference to the originally proposed idea in December: https://make.wordpress.org/core/2018/12/08/gutenberg-phase-2
A reference to the current proposed screencast: https://github.com/WordPress/gutenberg/issues/13205

Yet it’s continuously being stated that rapid development happening has made Gutenberg stay on track and increase productivity. I don’t disagree with that, but I also fail to see how it’s “meeting it’s roadmap’s objectives and deadlines on time.”

It’s also a bit concerning that two of the biggest contributors to the customizer’s recent state have iterated the same exact response to the initial proposal. “Why would you do it this way, and not use inline editing.” Reference to these remarks:
Weston Ruter (much of the current state of the customizer API, and primary influence of the JS API): https://make.wordpress.org/core/2018/12/08/gutenberg-phase-2/#comment-35031
Nick Halsey (responsible for menus added to customizer):
https://github.com/WordPress/gutenberg/issues/13205#issuecomment-455435023

I understand the reasoning, but the end goal of all this work is to get WordPress to a state of doing “frontend editing,” so why take a sidestep to change a UI and put forth work into integrating Gutenberg into a narrow window (customizer controls) when it’s intended to be used for editing content inline anyways. This is basically saying “we’ll do work now, and in the end it will all be thrown out because the next phase is to actually do frontend editing and we won’t need this anymore.”

From a development perspective, there’s been no mention of how all these changes will impact the current customizer’s API for plugins and especially themes. This is the only API themes can really use, and if the goal is to replace this API, it’d be nice to get some information regarding this. It was asked in slack previously, but no information was ever supplied. You can reference the original conversation here: https://wordpress.slack.com/archives/C0381N237/p1543767795004900

It seems like we have screencasts of active development efforts on bringing widgets to the customizer, but there’s not any publicly available code still. I guess this all just means that development of the feature is happening through “outside sources.” Any suggestions people have made to date have been discarded as “this is the goal for later, but right now we’re going to do what we want,” so community input hasn’t seemed to be very well accepted. I can only assume that this is possibly why there aren’t really any weekly meetings or activity happening in #core-customize on slack, and most of the questions asked there are pretty much just ignored.

It’s a bit disheartening as I’m really looking forward to the functionality and feature set offered as being THE solution to bridge page editing and live site customizations.